Tubing



Jan. 24, 1933. B. QUARNSTROM TUBING Filed May 2, 1930 Patented Jan. 24, 1933 UNITED? STATES PATENT. orr cr. I

mm L. owumsrnon, or DETROIT, MICHIGAN, ASSIGNOB 'ro mum! 'mm comm, or DETROIT, MICHIGAN, A som one-non or mrcmem TUBING or example, they 10 any of a number ways. 13

may be soldered by a lead and tin alloy, or

other molten sealing metals may be employed such as copper-silver solder, brazing metal, or copper welded, or welded with an alloy containing copper such as Monel or Constantan.

The present invention is concerned principally with a seam of the lap type. The overlapping parts are treated in such manner that a strong seam is provided. In this regard the sealing metal is afforded a very eflicient grip or bond with the treated edge. In one form of the invention the edges are so treated that additional strength is given to the tube structure, as the tube is strengthened against wall collapse when it is bent.

Ordinarily, such a tube is made up with solder, and in the following detailed description the term solder is employed but it is to "be understood that the invention embodies a scope, as to cover various kinds of sealing metals such as the ones above mentioned.

Fig. 1 is a sectional viewtaken through a tube constructed in accordance with the invention.

2 is a somewhat diagrammatical view in i ustration of devices for treating the ed es to be lapped.

ig. 3 is a sectional view taken through another form of the invention.

Fig. 4 is a perspective view of a tube illustrated in Fig. 3.

Fig. 5 is a somewhat diagrammatic view in illustration of means for treating the edges to be overlapped.

Fig. 6 is a sectional view taken on line 6-6 of Fig. 5.

The tube, as illustrated in Fig. 1, is com- 50 posed of apiece of sheet metal formed into hollow cross sectional shape, and one edge as" at 1, underlies the opposite edge as at 2. Preferably, the edge 1 is ofiset as at. 3 so that the outside of the tube does not have a projecting, shoulder formed by the extreme end of edge 2. It will be understood that this lap seam ma be directly longitudinally extending, as a ove mentioned, but it is within the invention that the seam be spiral or of undulating formation if occasion arises for having a seam thus formed.

The lapped portions 1 and 2 are to be soldered together, and for the purpose of providing an efiicient bond one or both of the overlapping edges are provided with a multiplicity of small depressions and raised por tions. In other words, they are roughened somewhat. This may be accomplished in the' making of the tube by utilizing rollers, as illustrated in Fig. 2. The strip stock is 7 passed lengthwise in the usual manner understood by those versed in the art, and it may be sent through two pairs of rollers, as illustrated, one pair has a knurled or roughened roller 5, and a smooth roller 6, while the other pair has a smooth roller 7 and a knurled roller 8. Sufiicient pressure is present to knurl the edges of the stock in contact with the knurling rollers. As the stock is formed into the hollow cross sectional shape by the usual forming rollers or dies, as is well, understood by those versed in the art,' 'the knurled parts face each other, as illustrated in Fig. 1. It will be understood that only one of the lapped partsmay be knurled if such be desired.

The overlapping parts are soldered to gether. This may be done in any of the well known manners, as by passing the tube through a heated chamber and subjecting the same to molten solder, as by means of pouring solder thereon, or by passing the tube through sweating dies. Also the stock may be previously tinned (provided with a coating of alloy of tin and lead) so that when heated, as by means of a sweating die or the like the solder becomes molten and seals the overlapping edges together. In any event the solder seats into the roughened or knurled parts and forms an effective bond.

. z y x 4 J Suitable flux or other equivalent materlals may be used in thesolderingegrocess; neutral atmosphere may be employ in the copper welding.

5 A variation of the invention, and one which stren ens the. tube structure per se is illustrate in,*F1gs. 3 and 4. Here the overlapping parts at and 11 are corrugated' with the corrugations extending transi m versely of the tube. While in the form shown in Fig. 1 the roughened or knurled formation may be placed at random, in the form .shown in Figs. 3 and 4 the corrugations are such as to i'nterfit as shown. The corrugating oi the edges may be accomplished by passing the stock throu h co-actlng corrugatedrollers 12 and 13 us corru ating the edge .as shown in Fig. & Inasmuc as these corrugations are to be spaced so that the pro-j m 'fections OIL one edge seat in the furrows of the other edge the-corru ting rollers 12 and 13 may advantageously positively driven. The corruga lap seam construction more or less binds thelapped edges together and effectively preventsopemng of the seam by any tendency to relative lon 'tudinal movement such as would occur w en the tube is subjected to twisting strains. In addition to" this the corrugated seameifectively stren h- 'ens the tube so that it does not so readily as I-claima bend stifiening as it were. 1 Yet this stiifening oes not causeethe walls to unduly collapseif it is .fonnd necessary to bend the tube into shapes for use.- I

A lap seam tube comprising a strip of metal fashioned into hollow cross sectional shape to form a smooth walled tube one edge of the strip being oflset radially of the tube, the

to longitudinal edges of the stri being lapped .one over the other with one e ge fitting upon the offset portion of the other edge, both of said lapped edges being corrugated with the corrugations extending substantially in a 4'5 circumferential direction with the body of the strip remainin smooth, said corru ations on the two Igesbein of similar'slze and sha e and inter tting w ereby the, edges are in c and Substantial contact through out the length ofthe tube, saidedgesbemg united'by'molten sealin' metal. Intestimon whereo Iafiixm si ature.

ERT L'Q 

